i think the community will increase with the time, too.
TM2: Canyon is a great opening for Maniaplanet (still some problems...loops *cough* wallrides *cough*), but it is just 1 envi at the moment. So it's not that huge game even if the possibilitys in the editor are awsome. I think at the moment TM2 is just like an updated TM which you can play some time instead of TMNF or TMUF.
But when the other envis will be released and also the first envis of shootmania and questmania (if they're going to be good games), the playerbase will increase dramatically. There is no shooter where a layman can build own maps and play them online. In the RPG section it's the same. And beside the included editor, you can create models with external programs. So what we get is a community based playerportal where the future is in the hands of the community.
Just give it some time. TM2 rocks, even with the loop/wallride problems. If the quality of the other games/envis will be the same, there is coming something great to us
